Die rotation system and method

ABSTRACT

A system and method for partially or completely inverting (rotating) a die and subsequently returning the die to its normal operating position. Systems of the invention include a roll-over unit that engages a roll frame or similar structure to which a die of interest is temporarily secured. The roll-over unit includes a drive motor that is used to rotate the roll frame and the die that is releasably coupled thereto. A deceleration assembly is provided to bring rotation of the die to a slow and controlled stop in one or both rotational directions. When the drive motor is a hydraulic motor, the deceleration assembly may include deceleration valves that are actuated by a rack gear that is caused to move linearly during rotation of the drive motor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/500,968, which was filed on Jun. 24, 2011 and is incorporated byreference herein.

TECHNICAL FIELD

The present invention is directed to a device for rotating a die, suchas but not limited to, a trim die.

BACKGROUND

It is well known that dies of various design are used in a number ofdifferent stamping, forming, and/or trimming processes. These processesmay involve, without limitation, the creation and/or alteration of sheetmetal parts or cast parts.

It would be understood by one of skill in the art that there may bevarious occasions within such a process wherein an associated die needsto be at least partially rotated (i.e., rolled-over to an inverted orpartially inverted orientation). One such example involves a trimmingdie used in a cast part trimming operation, where gates, runners, flash,etc., are trimmed/removed from a cast part. During such an operation, itis common for the trimmed part to be removed from the die and for thedie to subsequently traverse to a position where it is at leastpartially rotated so that the trimmed gates, runners, flash, etc., aredumped into a pit or other collection receptacle for transfer to afurnace for remelting.

It would also be understood by one of skill in the art that such diesare typically very heavy and, therefore, the transfer and particularlyrotation thereof may be difficult to accomplish smoothly. For example,when rotating a die, it is generally difficult to smoothly terminate theinverting rotational motion or the return (reverting) rotational motionof the die due to the inertia and momentum associated therewith. Rather,the use of known systems and methods for accomplishing die rotationtypically results in an abrupt and jarring termination of an invertingor reverting operation, typically from the die or a component to whichit is coupled impacting a hard stop. This may lead to damage to the diebeing rotated and/or to the device used to rotate the die.

Therefore, it would be desirable to provide a system and method forrotating a die that avoids the aforementioned jarring movement. Ideallysuch a system would also be robust, reliable, easy to service andtroubleshoot, and inexpensive to maintain. A die rotation system of thepresent invention is such a system.

SUMMARY

A die rotation system of the present invention is capable of smoothlyrotating (i.e., rolling over) a die to an inverted (meaning wholly orpartially inverted) position in a controlled manner and without theundesirable jarring or impact effects described above. A system of thepresent invention may be associated with or completely separate fromother devices or systems that are used to transfer the die betweenvarious positions, such as trimming, unloading, and inverted positions.

A system of the present invention generally includes a roll-over unitthat is coupled to a pivotable die support structure (e.g., roll frame)to which a die is temporarily and releasably secured. Embodiments of theroll-over unit are powered by a motor coupled to a drive mechanism. Inone exemplary embodiment, the drive motor is a hydraulic motor, whichturns a drive sprocket to which is connected a drive chain. The drivechain is used to rotate an inversion sprocket that is coupled, such asby a shaft, to the roll frame. Consequently, operation of the drivemotor causes a corresponding rotation of the inversion sprocket and arotation (flipping) of the roll frame and associated die.

The degree of die rotation may be controlled by use of a limit switch,proximity switch, or some other sensor adapted to detect die rotationand cause a reversal thereof once the die reaches some predeterminedinversion point. For example, upon reaching a desired inversion point, alimit switch may be tripped, which causes a reversal in the direction ofdrive motor rotation (e.g., by reversing the direction of flow ofhydraulic fluid) and a corresponding return (reversion) of the die toits upright position.

Embodiments of the present invention also include a decelerationassembly that acts to smoothly terminate the inversion and reversionrotational motion of the die. That is, the deceleration assemblyfunctions to smoothly decelerate and halt die inversion/reversion sothat the aforementioned jarring and impact effects of known systems areavoided.

To this end, embodiments of the present invention may be equipped withdeceleration valves that, when actuated, meter (restrict) the flow ofhydraulic fluid to slow the rotational movement of the die and reduce oreliminate impact forces associated with the end point of dieinversion/reversion.

In one embodiment, a pair of deceleration valves may be located near theinversion sprocket. The deceleration valves may be equipped withplungers or similar actuators. A rack gear may be positioned near thedeceleration valves such that movement of the rack gear by some amountin one direction will actuate one of the deceleration valves. Movementof the rack gear in an opposite direction will have the same effect onthe other deceleration valve. The rack gear may be linearly driven byrotation of a corresponding pinion coupled to the inversion sprocket.The deceleration assembly may also be associated with position sensors(e.g., limit switches, proximity switches) and appropriate actuatingelements that interact to reverse movement of the die. Alternatively,these position sensors may be located elsewhere.

BRIEF DESCRIPTION OF THE DRAWINGS

In addition to the features mentioned above, other aspects of thepresent invention will be readily apparent from the followingdescriptions of the drawings and exemplary embodiments, wherein likereference numerals across the several views refer to identical orequivalent features, and wherein:

FIGS. 1A-1C depict a lower half of an exemplary trim die as it movesfrom a post-trimming position within a trim press, to a roll-overengagement position, and then to an inverted position, in accordancewith the use of an exemplary die rotation system and method of thepresent invention;

FIG. 2 is a perspective view of a front side of one exemplary embodimentof a roll-over unit of the present invention;

FIG. 3 is a perspective view of a rear side of the roll-over unit ofFIG. 2;

FIG. 4 shows the roll-over unit of FIGS. 2-3 being used in conjunctionwith a coupled roll frame to rotate the lower die half of FIGS. 1A-1C;and

FIG. 5 is an enlarged view of a deceleration assembly viewable in FIGS.3 and 4.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT(S)

As stated above, a system and method of the present invention may beused to rotate a variety of die types. As an example, a trim die 5 forremoving gates, runners, flash, etc., from a cast part is shown in FIGS.1A-1C. As shown in FIG. 1A, the trim die 5 has completed the trimmingoperation and the die has been opened such that the lower and upper diehalves 10, 15 thereof are separated. Only the lower die half 10 isactually moved between a trimming position and a rotated positionaccording to the present invention. As shown in FIG. 1A, the lower diehalf 10 still resides within a trim press 70.

As shown in FIGS. 1B-1C, the lower die half 10 is transferred fromwithin the trim press 70 toward a dumping position, where it will berotated to dislodge trimmed materials into a receptacle 180. Transfer ofthe lower die half 10 to the dumping position may occur by any number ofdrive systems known in the art and used for such purposes and,therefore, such drive systems need not be further described herein.

When the lower die half 10 reaches the position shown in FIG. 1B, it isengaged by a die rotation system of the present invention for thepurpose of inverting or semi-inverting the lower die half 10 and causingaccumulated scrap to be dumped, as mentioned above. As can be observedin FIGS. 2-5, the die rotation system may include at least a roll frame20, a roll-over unit 25, and a deceleration system 100.

An exemplary roll-over unit 25 is illustrated in more detail in FIGS.2-3. As shown, the roll-over unit 25 includes a frame 30 to which thevarious components of the roll-over unit 25 may be attached. Theroll-over unit 25 also includes a drive motor 35 which, in this case, isa bi-directional (i.e., reversible) hydraulic drive motor. The drivemotor 35 is coupled to a drive gear 40 that extends toward the rollframe 20 (see FIG. 4) and is used to engage and rotate the die half 10.The roll-over unit 25 also includes an inversion gear 45 that isdesigned for coupling to the drive gear 40. In this particular example,the drive gear 40 and inversion gear 45 are designed to be coupled by adrive chain 185, but the use of other coupling arrangements (e.g.,belts) is also possible. In any event, it can be understood thatoperation of the drive motor 35 will produce a direct rotation of thedrive gear 40 which, in turn, will produce a rotation of the inversiongear 45.

As shown in FIG. 2, a roll-frame engagement and rotation element 50 iscoupled to the inversion gear 45 and extends in the same direction asthe drive gear 40. Preferably, a shaft portion of the roll-frameengagement and rotation element 50 passes through a bearing 55 forsupport and rotation facilitation. This particular roll-frame engagementand rotation element 50 includes an extending shaft 60 surrounded by acollar 65, which is provided to connect the output shaft of theinversion gear 45 to the roll frame 20. Obviously, a number of otherknown mechanisms may be used to couple the inversion gear 45 to the rollframe 20, and all such mechanisms are considered to be within the scopeof the present invention.

The relationship of the roll-over unit 25 to the roll frame 20, and usethereof to rotate the lower die half 10 is most clearly depicted in FIG.4. As shown therein, the roll frame 20 is basically a welded orotherwise securely assembled framework designed to receive and supportthe lower die half 10 once it traverses to the rotation position of FIG.1C. In this particular example, the roll frame 20 includes a generallyU-shaped connecting portion 22 having a transverse leg 24 thattransversely spans the travel path of the lower die half 10 and a pairof vertical legs, 26, 28 that extend from opposite ends of thetransverse leg 22 and are respectively connected between the roll-frameengagement and rotation element 50 of the roll-over unit 25 and abearing or other rotation facilitating element located across from theroll-over unit 25. This particular roll-over unit 25 also includes diesupport arms 32 that are attached to and extend from the transverse leg24 for supporting the lower die half 10. The roll frame 20 may resideand rotate at least partially within a pit or other recess located alongthe travel path of the lower die half 10 so that the roll frame 20 islocated at a proper height to receive the lower die half 10.

During a rotation operation, the lower die half 10 may be temporarilysecured to the roll frame 20 in various ways. In this particularexample, the lower die half 10 is equipped with guide blocks (not shown)that ride on and capture substantially T-shaped guide rails (not visiblein FIG. 4). The lower die half rides on these guide rails as ittraverses from the trim press 15 to the rotation position. Sections ofsuch T-shaped guide rail are attached to an upper surface of each diesupport arm 32, such that the lower die half 10 is able to smoothlytransition onto the roll frame 20. Further, because the guide rails aresecurely attached to the support arms 32 and also trapped within theguide blocks, the lower die half 10 remains secured to the rails and tothe roll frame 20 during die rotation. A hard stop or similar elementmay be located at a forward end of the guide rails to prevent a slidingmovement of the lower die half 10 during die rotation. In otherembodiments, clamps or other securing mechanisms may be used to secure adie half to a roll frame in lieu of or in addition to the guideblock/guide rail assembly described above.

Referring now to FIG. 5, it can be observed that the roll-over unit 25also includes a deceleration assembly 100. The deceleration assembly 100includes a pair of deceleration valves 105, 110 that are placed in fluidcommunication with a fluid supply block 115 (or directly with theinlet/outlet ports) of the hydraulic motor 35 by appropriate fluidconduit 120. Each deceleration valve 105, 110 includes an actuator, inthis case a plunger 125, 130, for activating the correspondingdeceleration valve.

As part of the deceleration assembly 100, a rack gear 135 is mounted toa frame or similar element (not shown) located rearward of the inversiongear 45. An associated pinion (e.g., spur gear) 140 is coupled to a rearof the inversion gear 45 or to a shaft portion thereof and positioned tobe engaged with the rack gear 135.

In operation, hydraulic fluid supplied to the drive motor 35 from apressurized source (not shown) either passes through the decelerationvalves 105, 110 or can be otherwise metered by the deceleration valves105, 110. With the roll frame 20 engaged with the roll-frame engagementand rotation element 50 of the roll-over unit 25, pressurized hydraulicfluid is supplied to the drive motor 35, causing the powered rotationthereof. This produces a corresponding rotation of the drive gear 40 andthe inversion gear 45, which causes a rotation of the roll frame 20 andlower die half 10 secured thereto (see FIG. 10 and FIG. 4).

As the inversion gear 45 rotates, the pinion 140 also rotates, therebycausing a linear translation of the rack gear 135 toward onedeceleration valve 105 or the other 110 (depending on the direction ofrotation of the inversion gear 45). For example, referring to FIGS. 3-5,it can be understood that as the inversion gear 45 is rotatedcounterclockwise to invert the lower die half 10 in this particularexample, the pinion 140 will cause the rack gear 135 to move linearlytoward the inversion deceleration valve 105. When the lower die half 10reaches some selected point prior to a predetermined degree of rotation,the rack gear 135 will contact and depress the plunger 125 of theinversion deceleration valve 105, which causes the inversiondeceleration valve to meter (restrict) the flow of hydraulic fluid tothe drive motor 35. This reduces the speed of die rotation and allowsthe die to reach an inverted stop point in a slow and controlled manner(without causing an adverse impact or jarring effect).

The same slow and controlled stopping of rotational die movement occurswhen the die is thereafter rotated (reverted) to its normal uprightposition. That is, as the inversion gear 45 is rotated clockwise torevert the lower die half 10 in this particular example, the pinion 140causes the rack gear 135 to move linearly toward the reversiondeceleration valve 110. When the lower die half 10 reaches some selectedpoint prior to its normal operating position, the rack gear 135 willcontact and depress the plunger 130 of the reversion deceleration valve110 (see FIG. 4), which causes the reversion deceleration valve 110 tometer (restrict) the flow of hydraulic fluid to the drive motor 35,thereby reducing the speed of die rotation and allowing the die to reacha normal operating stop point in a slow and controlled manner (withoutcausing an adverse impact or jarring effect).

As should be apparent from the drawing figures, the spacing between thedeceleration valves 105, 110, the length of the rack gear 135, the pitchof the rack gear 135 and pinion 140, and/or other parameters of thedeceleration assembly 100 and/or roll-over unit 25 may be adjusted toensure that the appropriate deceleration valve 105, 100 is activated bythe rack gear 135 at the proper time.

The overall degree of rotation of the roll frame 20 and associated lowerdie half 10, may be controlled through the use of sensors. In thisparticular exemplary embodiment, those sensors are in the form of limitswitches 150, 155. In other embodiments, the sensors may be proximityswitches, photo eyes, etc. The sensors may be located in various placesso as to be properly activated.

Referring to FIGS. 3 and 5, it can be observed that in this embodiment,limit switches 150, 155 are mounted near the deceleration assembly 100and corresponding limit switch trip levers 170, 175 are associated withan output shaft of the inversion gear 45. Consequently, rotation of theinversion gear 45 during die rotation also rotates the trip levers 170,175 and causes one or the other of the trip levers 170, 175 to contactone or the other of the limit switch actuator arms 160, 165, dependingon the direction of rotation of the inversion gear 45. For example, asthe inversion gear 45 rotates in a counterclockwise direction during adie inversion operation, the inversion trip lever 175 also rotatescounterclockwise until it contacts the inversion limit switch actuatorarm 160 and activates the inversion limit switch 150. This causes theinverting rotation of the lower die half 10 to stop and also reversesthe drive motor 35, thereby causing the lower die half 10 to be revertedto its normal operating position. When the lower die half 10 reaches itsnormal operating position, the reversion trip lever 170 contacts thereversion limit switch actuator arm 165 and activates the reversionlimit switch 155. A signal from the reversion limit switch 155 may beused, for example, to release an interlock and/or to signal a dietraversing mechanism to return the lower die half 10 to the trim press15.

While certain embodiments of the present invention are described indetail above, the scope of the invention is not to be considered limitedby such disclosure, and modifications are possible without departingfrom the spirit of the invention as evidenced by the following claims:

What is claimed is:
 1. A die rotation system for rotating a die betweenan upright position and an inverted position, comprising: a roll-overunit including at least a hydraulic drive motor and an inversion gearrotatably driven by the drive motor; a die support frame coupled to theroll-over unit; a deceleration mechanism for slowing the speed of dierotation prior to a stoppage thereof, the deceleration mechanismcomprising a deceleration assembly that includes a pair of decelerationvalves and a rack gear residing between the deceleration valves andlocated to independently actuate the deceleration valves when linearlydisplaced in one direction or an opposite direction; and a sensor forindicating a rotational position of the die.
 2. The die rotation systemof claim 1, wherein the pair of deceleration valves are located near theinversion gear, and a pinion is coupled to the inversion gear andengaged with the rack gear so as to linearly move the rack gear duringrotation of the inversion gear.
 3. The die rotation system of claim 2,wherein the rack gear is adapted to activate a corresponding one of thedeceleration valves during inverting and reverting die rotation.
 4. Thedie rotation system of claim 3, wherein the deceleration valves areadapted to restrict a flow of hydraulic fluid to the hydraulic drivemotor to slow the speed of die rotation prior to a stoppage thereof. 5.The die rotation system of claim 1, wherein a sensor for indicating adesired degree of die inversion and a sensor for indicating an uprightdie position are present.
 6. The die rotation system of claim 5, whereinthe sensors are limit switches located near the inversion gear, and anoutput shaft of the inversion gear is coupled to trip levers that arepositioned to selectively actuate the limit switches during inversionand reversion of a die.
 7. The die rotation system of claim 1, furthercomprising a mechanism for releasably securing a die to be rotated tothe die support frame during a rotation operation.
 8. The die rotationsystem of claim 7, wherein the mechanism for releasably securing a dieto be rotated to the die support frame includes guide slots in a lowerportion of the die to be rotated, the guide slots adapted for engagementwith corresponding guide rails attached to an upper surface of the diesupport frame.
 9. The die rotation system of claim 7, wherein themechanism for releasably securing a die to be rotated to the die supportframe is comprised of one or more clamps.
 10. A die rotation system forrotating a lower die half of a die between an upright position and aninverted position, comprising: a roll-over unit including at least ahydraulic drive motor and an inversion gear rotatably driven by thedrive motor; a pivotable roll frame for supporting a die to be rotated,the roll frame rotatably coupled to the roll-over unit; a mechanism forreleasably securing a die to be rotated to the roll frame during arotation operation; a deceleration assembly including a pair ofdeceleration valves located near the inversion gear, a rack gearresiding between the deceleration valves and located to independentlyactuate the deceleration valves when linearly displaced in one directionor an opposite direction, and a pinion coupled to the inversion gear andengaged with the rack gear so as to linearly move the rack gear duringrotation of the inversion gear; at least one sensor for indicating adesired degree of die inversion and for indicating an upright dieposition; wherein, the rack gear is adapted to activate a correspondingone of the deceleration valves during inverting and reverting dierotation, and wherein the deceleration valves are adapted to restrict aflow of hydraulic fluid to the drive motor to slow the speed of dierotation prior to a stoppage thereof.
 11. The die rotation system ofclaim 10, wherein the roll-over unit further includes a frame and adrive gear coupled to the drive motor, the drive gear coupled to theinversion gear such that operation of the hydraulic motor produces arotation of the inversion gear.
 12. The die rotation system of claim 10,wherein the roll frame is coupled to a roll-frame engagement androtation element that is, in turn, coupled to the inversion gear andextends in the same direction as the drive gear.
 13. The die rotationsystem of claim 12, wherein the roll-frame engagement and rotationelement includes an extending shaft surrounded by a collar, which isprovided to connect the output shaft of the inversion gear to the rollframe.
 14. The die rotation system of claim 12, wherein the roll frameincludes a connecting portion with a transverse leg that transverselyspans a travel path of the lower die half, and a pair of vertical legsthat extend from opposite ends of the transverse leg and arerespectively connected between the roll-frame engagement and rotationelement and a rotation facilitating element located across from theroll-over unit.
 15. The die rotation system of claim 10, wherein theroll frame includes die support arms for supporting the lower die half,with guide rails attached to an upper surface of the support arms andcorresponding guide slots located in a lower portion of a lower die halfto be rotated, the guide slots and guide rails adapted to collectivelysecure the lower die half to the roll frame during die rotation.
 16. Thedie rotation system of claim 10, wherein the at least one sensor is apair of limit switches located near the inversion gear, and an outputshaft of the inversion gear is coupled to trip levers that arepositioned to selectively actuate the limit switches during inversionand reversion of a lower die half.
 17. A method of rotating a lower diehalf of a die between an upright position and an inverted position,comprising: transferring a die half of interest from a working locationonto the roll frame of the die rotation system of claim 10; using thedie rotation system to invert the lower die half; using the die rotationsystem to revert the lower die half; and returning the lower die half tothe working location.